The chemical properties of titanium dioxide are very stable. As a kind of acidic amphoteric oxide, Tio2 does not act with other elements and compounds at normal temperature, and it does not act on oxygen, ammonia, nitrogen, hydrogen sulfide, carbon dioxide, and sulfur dioxide. It is insoluble in water, dilute acid and weak inorganic acid.

Titanium dioxide can dissolve in hydrofluoric acid, generating a fluorine titanate. When boiling for a long time, titanium dioxide can be dissolved in concentrated sulfuric acid to produce titanium sulfate or titanium sulfate. Titanium dioxide can also be dissolved in alkali, such as strong alkali (sodium hydroxide, potassium hydroxide) or alkali metal carbonate (sodium carbonate and potassium carbonate), and converted to titanate which is soluble in acid.

Titanium dioxide suspended in some organic medium can be circularly reduced and oxidized under the action of light and air, resulting in the oxidation of the medium. This is a photochemical activity that is particularly evident in the anatase titanium dioxide form under ultraviolet radiation. This characteristic makes titanium dioxide not only a photosensitive oxidation catalyst for some inorganic compounds, but also a photosensitive reduction catalyst for some organic compounds.

Barium titanate is produced with barium carbonate (barium chloride or sodium carbonate as a cosolvent).

TiO2+BaCO3=BaTiO3+CO2

Do not dissolve in water or dilute sulfuric acid, but soluble in hot concentrated sulfuric acid or molten potassium bisulfate:

TiO2+H2SO4=TiOSO4+H2O

Although the solution of titanium dioxide dissolved in hot concentrated sulfuric acid is acidic, it can also be hydrolyzed by heating and boiling to obtain hydrated titanium dioxide (beta type titanate) which is insoluble in acid and alkali. If we add alkali to the new titanium hydrochloric acid solution, we get fresh hydrated titanium dioxide (A-type titanate). Its reaction activity is greater than that of beta type titanate, and it can be dissolved in dilute acid and strong alkali. After solution of concentrated sodium hydroxide solution, the chemical formula of Na2TiO3 H2O hydrate titanate can be precipitated from the solution.

Titanium dioxide and carbon powder are pressed into groups and coked and heated to 1070-1170K, which can be used to produce four titanium chloride.

TiO2+2Cl2+2C=TiCl4↑+2CO↑

This reaction is important for refining titanium, and magnesium or sodium can simplify the reduction of four titanium chloride. The reaction of titanium dioxide with COCl2 (phosgene), SOCl2 (two chlorine sulfoxide), CHCl3 (trichloromethane), CCl4 (carbon tetrachloride) and other chlorination reagents can also be used to produce four titanium chloride.

TiO2+CCl4=TiCl4↑+2CO2↑  (the reaction is completed under 770K)